Safe Haskell	Safe-Inferred
Language	Haskell98

System.Clock

Description

High-resolution, realtime clock and timer functions for Posix systems. This module is being developed according to IEEE Std 1003.1-2008: http://www.opengroup.org/onlinepubs/9699919799/, http://www.opengroup.org/onlinepubs/9699919799/functions/clock_getres.html#

Synopsis

data Clock
- = Monotonic
- | Realtime
- | ProcessCPUTime
- | ThreadCPUTime
- | MonotonicRaw
- | Boottime
- | MonotonicCoarse
- | RealtimeCoarse
data TimeSpec = TimeSpec {
- sec :: !Int64
- nsec :: !Int64
}
getTime :: Clock -> IO TimeSpec
getRes :: Clock -> IO TimeSpec
fromNanoSecs :: Integer -> TimeSpec
toNanoSecs :: TimeSpec -> Integer
diffTimeSpec :: TimeSpec -> TimeSpec -> TimeSpec
timeSpecAsNanoSecs :: TimeSpec -> Integer

Documentation

data Clock #

Clock types. A clock may be system-wide (that is, visible to all processes) or per-process (measuring time that is meaningful only within a process). All implementations shall support CLOCK_REALTIME. (The only suspend-aware monotonic is CLOCK_BOOTTIME on Linux.)

Constructors

Monotonic	The identifier for the system-wide monotonic clock, which is defined as a clock measuring real time, whose value cannot be set via `clock_settime` and which cannot have negative clock jumps. The maximum possible clock jump shall be implementation defined. For this clock, the value returned by `getTime` represents the amount of time (in seconds and nanoseconds) since an unspecified point in the past (for example, system start-up time, or the Epoch). This point does not change after system start-up time. Note that the absolute value of the monotonic clock is meaningless (because its origin is arbitrary), and thus there is no need to set it. Furthermore, realtime applications can rely on the fact that the value of this clock is never set.
Realtime	The identifier of the system-wide clock measuring real time. For this clock, the value returned by `getTime` represents the amount of time (in seconds and nanoseconds) since the Epoch.
ProcessCPUTime	The identifier of the CPU-time clock associated with the calling process. For this clock, the value returned by `getTime` represents the amount of execution time of the current process.
ThreadCPUTime	The identifier of the CPU-time clock associated with the calling OS thread. For this clock, the value returned by `getTime` represents the amount of execution time of the current OS thread.
MonotonicRaw	(since Linux 2.6.28; Linux-specific) Similar to CLOCK_MONOTONIC, but provides access to a raw hardware-based time that is not subject to NTP adjustments or the incremental adjustments performed by adjtime(3).
Boottime	(since Linux 2.6.39; Linux-specific) Identical to CLOCK_MONOTONIC, except it also includes any time that the system is suspended. This allows applications to get a suspend-aware monotonic clock without having to deal with the complications of CLOCK_REALTIME, which may have discontinuities if the time is changed using settimeofday(2).
MonotonicCoarse	(since Linux 2.6.32; Linux-specific) A faster but less precise version of CLOCK_MONOTONIC. Use when you need very fast, but not fine-grained timestamps.
RealtimeCoarse	(since Linux 2.6.32; Linux-specific) A faster but less precise version of CLOCK_REALTIME. Use when you need very fast, but not fine-grained timestamps.

Instances

Instances details

Enum Clock #
Instance details Defined in System.Clock Methods succ :: Clock -> Clock pred :: Clock -> Clock toEnum :: Int -> Clock fromEnum :: Clock -> Int enumFrom :: Clock -> [Clock] enumFromThen :: Clock -> Clock -> [Clock] enumFromTo :: Clock -> Clock -> [Clock] enumFromThenTo :: Clock -> Clock -> Clock -> [Clock]
Eq Clock #
Instance details Defined in System.Clock Methods (==) :: Clock -> Clock -> Bool (/=) :: Clock -> Clock -> Bool
Read Clock #
Instance details Defined in System.Clock Methods readsPrec :: Int -> ReadS Clock readList :: ReadS [Clock] readPrec :: ReadPrec Clock readListPrec :: ReadPrec [Clock]
Show Clock #
Instance details Defined in System.Clock Methods showsPrec :: Int -> Clock -> ShowS show :: Clock -> String showList :: [Clock] -> ShowS
Generic Clock #
Instance details Defined in System.Clock Associated Types type Rep Clock :: Type -> Type Methods from :: Clock -> Rep Clock x to :: Rep Clock x -> Clock
type Rep Clock #
Instance details Defined in System.Clock type Rep Clock = D1 ('MetaData "Clock" "System.Clock" "clock-0.8-4lBJpsoJnaMAEksLJJCwUa" 'False) (((C1 ('MetaCons "Monotonic" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "Realtime" 'PrefixI 'False) (U1 :: Type -> Type)) :+: (C1 ('MetaCons "ProcessCPUTime" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "ThreadCPUTime" 'PrefixI 'False) (U1 :: Type -> Type))) :+: ((C1 ('MetaCons "MonotonicRaw" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "Boottime" 'PrefixI 'False) (U1 :: Type -> Type)) :+: (C1 ('MetaCons "MonotonicCoarse" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "RealtimeCoarse" 'PrefixI 'False) (U1 :: Type -> Type))))

data TimeSpec #

TimeSpec structure

Constructors

TimeSpec
Fields sec :: !Int64 seconds nsec :: !Int64 nanoseconds

Instances

Instances details

Eq TimeSpec #
Instance details Defined in System.Clock Methods (==) :: TimeSpec -> TimeSpec -> Bool (/=) :: TimeSpec -> TimeSpec -> Bool
Num TimeSpec #
Instance details Defined in System.Clock Methods (+) :: TimeSpec -> TimeSpec -> TimeSpec (-) :: TimeSpec -> TimeSpec -> TimeSpec (*) :: TimeSpec -> TimeSpec -> TimeSpec negate :: TimeSpec -> TimeSpec abs :: TimeSpec -> TimeSpec signum :: TimeSpec -> TimeSpec fromInteger :: Integer -> TimeSpec
Ord TimeSpec #
Instance details Defined in System.Clock Methods compare :: TimeSpec -> TimeSpec -> Ordering (<) :: TimeSpec -> TimeSpec -> Bool (<=) :: TimeSpec -> TimeSpec -> Bool (>) :: TimeSpec -> TimeSpec -> Bool (>=) :: TimeSpec -> TimeSpec -> Bool max :: TimeSpec -> TimeSpec -> TimeSpec min :: TimeSpec -> TimeSpec -> TimeSpec
Read TimeSpec #
Instance details Defined in System.Clock Methods readsPrec :: Int -> ReadS TimeSpec readList :: ReadS [TimeSpec] readPrec :: ReadPrec TimeSpec readListPrec :: ReadPrec [TimeSpec]
Show TimeSpec #
Instance details Defined in System.Clock Methods showsPrec :: Int -> TimeSpec -> ShowS show :: TimeSpec -> String showList :: [TimeSpec] -> ShowS
Generic TimeSpec #
Instance details Defined in System.Clock Associated Types type Rep TimeSpec :: Type -> Type Methods from :: TimeSpec -> Rep TimeSpec x to :: Rep TimeSpec x -> TimeSpec
Storable TimeSpec #
Instance details Defined in System.Clock Methods sizeOf :: TimeSpec -> Int alignment :: TimeSpec -> Int peekElemOff :: Ptr TimeSpec -> Int -> IO TimeSpec pokeElemOff :: Ptr TimeSpec -> Int -> TimeSpec -> IO () peekByteOff :: Ptr b -> Int -> IO TimeSpec pokeByteOff :: Ptr b -> Int -> TimeSpec -> IO () peek :: Ptr TimeSpec -> IO TimeSpec poke :: Ptr TimeSpec -> TimeSpec -> IO ()
type Rep TimeSpec #
Instance details Defined in System.Clock type Rep TimeSpec = D1 ('MetaData "TimeSpec" "System.Clock" "clock-0.8-4lBJpsoJnaMAEksLJJCwUa" 'False) (C1 ('MetaCons "TimeSpec" 'PrefixI 'True) (S1 ('MetaSel ('Just "sec") 'SourceUnpack 'SourceStrict 'DecidedStrict) (Rec0 Int64) :*: S1 ('MetaSel ('Just "nsec") 'SourceUnpack 'SourceStrict 'DecidedStrict) (Rec0 Int64)))

getTime :: Clock -> IO TimeSpec #

The getTime function shall return the current value for the specified clock.

getRes :: Clock -> IO TimeSpec #

The getRes function shall return the resolution of any clock. Clock resolutions are implementation-defined and cannot be set by a process.

fromNanoSecs :: Integer -> TimeSpec #

TimeSpec from nano seconds.

toNanoSecs :: TimeSpec -> Integer #

TimeSpec to nano seconds.

diffTimeSpec :: TimeSpec -> TimeSpec -> TimeSpec #

Compute the absolute difference.

timeSpecAsNanoSecs :: TimeSpec -> Integer #

Deprecated: Use toNanoSecs instead! Replaced timeSpecAsNanoSecs with the same signature TimeSpec -> Integer

TimeSpec as nano seconds.